Nonlinear Chemical Dynamics

Brandeis University, Waltham MA

Investigators

Abstract

CHE-1362477: Irving Epstein, Brandeis University, "Nonlinear Chemical Dynamics" Irving Epstein of Brandeis University is funded by the Chemical Structure, Dynamics and Mechanisms A program for research to deepen our understanding of chemical systems that operate far from thermodynamic equilibrium. One question the researchers are investigating involves the chemical mechanism of the development of form in an embryo, a process known as morphogenesis. Experiments are underway in this research project to more fully test a suggestion made over fifty years ago by the late Alan Turing that patterns in biology arise from a particular type of chemical pattern that also exists in nonliving systems. In other experiments, the investigators are building connected groups of model nerve cells to mimic and study communication networks in the brain. Other experiments are using gels and a specially-designed reactor to try to capture and preserve chemical patterns that have been observed in previous studies but, to date, only as fleeting and transient patterns. Because these studies are specifically designed to mimic certain behaviors in biological systems, such as communications between neurons and the development of form in embryos, the work helps us understand key life processes. Broader impacts of this work are the education of future scientists and the inclusion of otherwise under-represented groups in science. The Science Posse project, a mentoring and outreach program designed by Epstein as part of this research project, has received national recognition for its success in recruiting and maintaining a diverse group of STEM students. Other outreach efforts include the Science Café project, designed to bring science to the public, and a series of YouTube videos. In this research project, the investigators are building an open flow reactor for the study of emulsions consisting of 10-50 nm sized droplets of the Belousov-Zhabotinsky (BZ) reaction mixture. They are also seeking to determine the conditions under which chemical oscillators other than the BZ system can be introduced into nano-emulsions and will study pattern formation in these other chemical systems. The group is exploring whether the patterns that arise in emulsions can be "frozen in" to yield gels or solids that might have novel optical, electrical or mechanical properties and, thus, might be useful for developing new devices. Another study involves a hexagonal droplet array of 100 nm BZ drops. Previous observation has revealed that the drops first undergo chemical differentiation to produce either a reduced or an oxidized steady state. Subsequent physical differentiation occurs and the droplets are observed to either shrink or swell. Finally, new experiments are being carried out to synthesize gels containing the BZ catalyst attached to a conducting polymer backbone. Other experiments involve finding ways to attach new catalysts for the Briggs-Rauscher oscillator to polymers.